Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.

Abstract: The devices, systems, and methods of the present disclosure are directed to powder spreading and binder distribution techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, a powder may be spread to form a layer along a volume defined by a powder box, a binder may be deposited along the layer to form a layer of a three-dimensional object, and the direction of spreading the layer and depositing the binder may be in a first direction and in a second direction, different from the first direction, thus facilitating rapid formation of the three-dimensional object with each passage of the print carriage over the volume. Powder delivery, powder spreading, thermal energy delivery, and combinations thereof, may facilitate consistently achieving quality standards as the rate of fabrication of the three-dimensional object is increased.

Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.

Abstract: The devices, systems, and methods of the present disclosure are directed to powder spreading and binder distribution techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, a powder may be spread to form a layer along a volume defined by a powder box, a binder may be deposited along the layer to form a layer of a three-dimensional object, and the direction of spreading the layer and depositing the binder may be in a first direction and in a second direction, different from the first direction, thus facilitating rapid formation of the three-dimensional object with each passage of the print carriage over the volume. Powder delivery, powder spreading, thermal energy delivery, and combinations thereof, may facilitate consistently achieving quality standards as the rate of fabrication of the three-dimensional object is increased.

Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.

Abstract: Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. Electric current delivered to a meniscus of the liquid metal in a quiescent state can be directed to exert a pullback force on the liquid metal. The pullback force can be sufficient to draw the liquid metal, in the quiescent state, in a direction toward the nozzle to reduce the likelihood of unintended wetting of surfaces of the nozzle between uses of the nozzle.

Abstract: A dross removal system for magnetohydrodynamic additive. A vacuum source is used to create a pressure differential at a nozzle opening sufficient to collect dross from a pool of molten metal. The dross and any collected molten metal can be captured in a waste bin for later disposal.

Abstract: Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. Electric current delivered to a meniscus of the liquid metal in a quiescent state can be directed to exert a pullback force on the liquid metal. The pullback force can be sufficient to draw the liquid metal, in the quiescent state, in a direction toward the nozzle to reduce the likelihood of unintended wetting of surfaces of the nozzle between uses of the nozzle.

Abstract: For conditioning build material for fused filament fabrication, thermal power is both added to and removed from a nozzle in a manner that can reduce sensitivity of the nozzle temperature to fluctuations in build material feed rate. The amount of thermal power added is at least as large as the sum of the amount removed, the amount to condition the material, and losses to the environment. The amount removed may be at least as large as half the thermal power required to condition the material to extrusion temperature, and may be comparable to, or much larger than the conditioning amount. The larger the ratio of the amount removed to the conditioning amount, the less sensitive the nozzle temperature will be to fluctuations in build material feed rate. Fine temperature control arises, enabling building with metal-containing multi-phase materials or other materials that have a narrow working temperature range.

Abstract: Systems and methods are disclosed for forming a three-dimensional object using additive manufacturing. One method includes depositing a first amount of powder material onto a powder print bed of a printing system, spreading the first amount of powder material across the powder print bed to form a first layer, measuring a density of powder material within the powder print bed, and adjusting a parameter of the printing system based on the measured density of the powder material within the powder print bed.

Abstract: An improved additive manufacturing system for manufacturing metal parts by magnetohydrodynamic printing liquid metal. A monitoring system including at least one camera capturing light reflected from a strobe light source. Images of the droplets are captured during their jetting and analyzed to determine whether the jetting performance is meeting specifications. A nozzle of the system has a nozzle bottom and a nozzle stem extending outward therefrom on which a meniscus of liquid metal can form. The nozzle is cleaned by bringing a ceramic rod in the vicinity of the nozzle and jetting a bead of metal which is rotated against the nozzle to remove an amount of dross.

Abstract: A method of additive manufacturing using magnetohydrodynamic (MHD) printing of liquid metal. A first current pulse is applied to a liquid metal in a nozzle to eject a droplet from a discharge orifice. A second current pulse is applied to the liquid metal in the nozzle to reduce an amplitude of the oscillations in a meniscus on the discharge orifice. The second current pulse can be either of an opposite or the same polarity as the first current pulse and is timed according to according to the oscillation.

Abstract: The devices, systems, and methods of the present disclosure are directed to spreader positioning techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, an additive manufacturing system may include a roller and a print carriage. In a layer-by-layer fabrication process, the roller may move in advance of the print carriage over a dimension of a volume to spread a respective layer of powder onto which the print carriage delivers a binder. Controlling the position of the roller may facilitate achieving consistent layer characteristics which, in turn, may facilitate fabrication of high quality parts.

Abstract: A nozzle assembly for metal additive manufacturing using magnetohydrodynamic jetting. A nozzle defines a reservoir and a discharge region having a discharge orifice. A thick film heating system disposed on an exterior of the nozzle and including a first contact pad and a second contact pad connected by a heating pathway heats build material in the nozzle to a liquid state. A first electrode and a second electrode together configured to deliver an electrical current through the liquid build material in the discharge region while a magnet system delivers a magnetic field perpendicular the electrical current, thereby jetting liquid metal to form successive build layers.

Abstract: A method of developing a frequency map for an MHD jetting nozzle includes filling the MHD jetting nozzle with a liquid metal. The MHD jetting nozzle is excited with a series of jetting pulses delivered at a range of frequencies the vibration response of the MHD jetting nozzle and/or a meniscus of jetting material is measured.

Abstract: The devices, systems, and methods of the present disclosure are directed to powder spreading and binder distribution techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, a powder may be spread to form a layer along a volume defined by a powder box, a binder may be deposited along the layer to form a layer of a three-dimensional object, and the direction of spreading the layer and depositing the binder may be in a first direction and in a second direction, different from the first direction, thus facilitating rapid formation of the three-dimensional object with each passage of the print carriage over the volume. Powder delivery, powder spreading, thermal energy delivery, and combinations thereof, may facilitate consistently achieving quality standards as the rate of fabrication of the three-dimensional object is increased.

Abstract: Disclosed is a method and material system for fabricating metal infiltrated objects having a high volume fraction of infiltrant relative to the infiltrated preform. In an embodiment method, a composite is formed into the shape of a desired object, the composite including a skeletal phase and a fugitive phase. The fugitive phase is then removed to create a self-supporting porous skeletal structure. The porous skeletal structure is then infiltrated with the infiltrant to achieve a densified object.

Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.

Abstract: 3D printing using certain materials, such as metal containing multi-phase materials can be prone to clogs and other flow interruptions. Providing build material according to feed rate profiles having varying rates can mitigate these problems. Each feed rate profile can be broken up into blocks of time, some of which relate to fabricating the exterior geometry of the object. Each block of time can be represented by a FFT. The blocks that relate to the exterior are represented by a FFT that has significant high frequency content of 1 Hz or greater. It is beneficial to use profiles including feed rates outside of a range of feed rates suitable for steady state extrusion, being either higher or lower rates than the range limits. A combination of feed rate profiles based only on clog and flow interruption mitigation and operational to print the part according to a model can be used.

Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.